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Biassociahedra Revisited Joint work with Samson Saneblidze Ron - - PowerPoint PPT Presentation

Biassociahedra Revisited Joint work with Samson Saneblidze Ron Umble, Millersville U Lehigh Geometry/Topology Conference Honoring Don Davis on the occassion of his 70th birthday May 23, 2015 A-infinity Bialgebras Biassociahedron KK n , m


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SLIDE 1

Biassociahedra Revisited

Joint work with Samson Saneblidze Ron Umble, Millersville U Lehigh Geometry/Topology Conference Honoring Don Davis on the occassion of his 70th birthday May 23, 2015

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SLIDE 2

A-infinity Bialgebras

Biassociahedron KKn,m is a contractible (m + n − 3)-polytope

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SLIDE 3

A-infinity Bialgebras

Biassociahedron KKn,m is a contractible (m + n − 3)-polytope With a single top dimensional cell em+n−3

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SLIDE 4

A-infinity Bialgebras

Biassociahedron KKn,m is a contractible (m + n − 3)-polytope With a single top dimensional cell em+n−3 KKn,m ∼

= KKm,n

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SLIDE 5

A-infinity Bialgebras

Biassociahedron KKn,m is a contractible (m + n − 3)-polytope With a single top dimensional cell em+n−3 KKn,m ∼

= KKm,n

Stasheff’s associahedron Kn = KK1,n

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SLIDE 6

A-infinity Bialgebras

Let C∗ (KK) denote the cellular chains of KKn,m

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SLIDE 7

A-infinity Bialgebras

Let C∗ (KK) denote the cellular chains of KKn,m An A∞-bialgebra is a graded module H with operations

  • θn

m : H⊗m → H⊗n m,n≥1

and a chain map C∗ (KK) → End (TH) em+n−3 → θn

m

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SLIDE 8

A-infinity Bialgebras

Over a field, H∗ (ΩX) has an induced A∞-bialgebra structure

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SLIDE 9

A-infinity Bialgebras

Over a field, H∗ (ΩX) has an induced A∞-bialgebra structure Extends the A∞-algebra structure discovered by Kadeishvili

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SLIDE 10

A-infinity Bialgebras

Over a field, H∗ (ΩX) has an induced A∞-bialgebra structure Extends the A∞-algebra structure discovered by Kadeishvili Transfer DG bialgebra structure along a cycle-selecting map

H∗ (ΩX) → S∗ (ΩX)

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SLIDE 11

Biassociahedra

Cells of KKn,m are indexed by m-in/n-out directed graphs

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SLIDE 12

Biassociahedra

Cells of KKn,m are indexed by m-in/n-out directed graphs em+n−3 ←

→ n outputs m inputs

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SLIDE 13

Biassociahedra

Cells of KKn,m are indexed by m-in/n-out directed graphs em+n−3 ←

→ n outputs m inputs

{Vertices} ↔ {Certain binary graphs}

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SLIDE 14

Biassociahedra

Cells of KKn,m are indexed by m-in/n-out directed graphs em+n−3 ←

→ n outputs m inputs

{Vertices} ↔ {Certain binary graphs} When n = 1, graphs are uprooted trees

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SLIDE 15

Biassociahedra

Compositions in End (TH) are “fraction products”

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SLIDE 16

Biassociahedra

Compositions in End (TH) are “fraction products” If g f = 0

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SLIDE 17

Biassociahedra

Compositions in End (TH) are “fraction products” If g f = 0

# outputs from each factor of f = # of factors in g

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SLIDE 18

Biassociahedra

Compositions in End (TH) are “fraction products” If g f = 0

# outputs from each factor of f = # of factors in g # inputs to each factor of g = # of factors in f

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SLIDE 19

Biassociahedra

Compositions in End (TH) are “fraction products” If g f = 0

# outputs from each factor of f = # of factors in g # inputs to each factor of g = # of factors in f

{Binary graphs} ↔

{Compositions involving mult and comult }

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SLIDE 20

Biassociahedra

KK2,2

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SLIDE 21

Biassociahedra

KK2,3

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SLIDE 22

Biassociahedra

Our construction of KKn,m has four steps:

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SLIDE 23

Biassociahedra

Our construction of KKn,m has four steps:

Insert subdivision vertices into the permutahedron Pm+n−2

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SLIDE 24

Biassociahedra

Our construction of KKn,m has four steps:

Insert subdivision vertices into the permutahedron Pm+n−2 Extend the vertex poset structure to subdivision vertices

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SLIDE 25

Biassociahedra

Our construction of KKn,m has four steps:

Insert subdivision vertices into the permutahedron Pm+n−2 Extend the vertex poset structure to subdivision vertices Use poset structure to propagate subdivision to higher cells

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SLIDE 26

Biassociahedra

Our construction of KKn,m has four steps:

Insert subdivision vertices into the permutahedron Pm+n−2 Extend the vertex poset structure to subdivision vertices Use poset structure to propagate subdivision to higher cells Project to an appropriate quotient

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SLIDE 27

Biassociahedra

Our construction of KKn,m has four steps:

Insert subdivision vertices into the permutahedron Pm+n−2 Extend the vertex poset structure to subdivision vertices Use poset structure to propagate subdivision to higher cells Project to an appropriate quotient

2011 construction inserts too many subdivision vertices, e.g.

z = is not an admissible vertex of KK4,4

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SLIDE 28

Biassociahedra

Our construction of KKn,m has four steps:

Insert subdivision vertices into the permutahedron Pm+n−2 Extend the vertex poset structure to subdivision vertices Use poset structure to propagate subdivision to higher cells Project to an appropriate quotient

2011 construction inserts too many subdivision vertices, e.g.

z = is not an admissible vertex of KK4,4

The goal of this talk is to identify the issue and indicate a fix

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SLIDE 29

Permutahedra

P1 = ∗

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SLIDE 30

Permutahedra

P1 = ∗ P2 = I

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SLIDE 31

Permutahedra

P1 = ∗ P2 = I P3 is a hexagon

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SLIDE 32

Permutahedra

P4 is a solid truncated octahedron

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SLIDE 33

Permutahedra

P4 is a solid truncated octahedron Pn is an (n − 1)-dim’l contractible polytope

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SLIDE 34

Combinatorics of Permutahedra

Let n = {1, 2, . . . n}

{Cells of Pn in codim p} ↔ {Partitions U1| · · · |Up+1 of n}

↔ {Planar trees with p + 1 levels and n + 1 leaves}

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SLIDE 35

Combinatorics of Permutahedra

Let n = {1, 2, . . . n}

{Cells of Pn in codim p} ↔ {Partitions U1| · · · |Up+1 of n}

↔ {Planar trees with p + 1 levels and n + 1 leaves}

{Vertices of Pn} ↔ Sn ↔ {Binary trees with n levels}

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SLIDE 36

Combinatorics of Permutahedra

Let n = {1, 2, . . . n}

{Cells of Pn in codim p} ↔ {Partitions U1| · · · |Up+1 of n}

↔ {Planar trees with p + 1 levels and n + 1 leaves}

{Vertices of Pn} ↔ Sn ↔ {Binary trees with n levels} P1 : ∗ ↔ 1 ↔

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SLIDE 37

Combinatorics of Permutahedra

Let n = {1, 2, . . . n}

{Cells of Pn in codim p} ↔ {Partitions U1| · · · |Up+1 of n}

↔ {Planar trees with p + 1 levels and n + 1 leaves}

{Vertices of Pn} ↔ Sn ↔ {Binary trees with n levels} P1 : ∗ ↔ 1 ↔ P2 : edge ↔ 12 ↔

{vertices} ↔ {1|2, 2|1} ↔

  • ,
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SLIDE 38

Combinatorics of Permutahedra

P3

  • 123

1|2|3 1|3|2 3|1|2 2|1|3 2|3|1 3|2|1 1|23 3|12 13|2 23|1 2|13 12|3

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SLIDE 39

Vertices of Permutahedra

Pm × Pn embeds in Pm+n via em × en → em| (en + m)

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SLIDE 40

Vertices of Permutahedra

Pm × Pn embeds in Pm+n via em × en → em| (en + m) Embedding of P1 × P2 in P3 :

1 × 1|2 → 1|2|3 1 × 2|1 → 1|3|2 1 × 12 → 1|23

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SLIDE 41

Vertices of Permutahedra

Pm × Pn embeds in Pm+n via em × en → em| (en + m) Embedding of P1 × P2 in P3 :

1 × 1|2 → 1|2|3 1 × 2|1 → 1|3|2 1 × 12 → 1|23

(m, n) -shuffles on vertices of Pm × Pn generate vertices of Pm+n

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SLIDE 42

Vertices of Permutahedra

Pm × Pn embeds in Pm+n via em × en → em| (en + m) Embedding of P1 × P2 in P3 :

1 × 1|2 → 1|2|3 1 × 2|1 → 1|3|2 1 × 12 → 1|23

(m, n) -shuffles on vertices of Pm × Pn generate vertices of Pm+n {Vertices of P3} = shuff (1, 2|3) ∪ shuff (1, 3|2) =

{1|2|3, 2|1|3, 2|3|1} ∪ {1|3|2, 3|1|2, 3|2|1}

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SLIDE 43

S-U Diagonal on Permutahedra (2004)

C∗ (Pn) denotes the cellular chains of Pn

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SLIDE 44

S-U Diagonal on Permutahedra (2004)

C∗ (Pn) denotes the cellular chains of Pn ∆P : C∗ (Pn) → C∗ (Pn) ⊗ C∗ (Pn)

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SLIDE 45

S-U Diagonal on Permutahedra (2004)

C∗ (Pn) denotes the cellular chains of Pn ∆P : C∗ (Pn) → C∗ (Pn) ⊗ C∗ (Pn) S-U agrees with A-W on P1 and P2 :

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SLIDE 46

S-U Diagonal on Permutahedra (2004)

C∗ (Pn) denotes the cellular chains of Pn ∆P : C∗ (Pn) → C∗ (Pn) ⊗ C∗ (Pn) S-U agrees with A-W on P1 and P2 :

∆P () = ⊗

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SLIDE 47

S-U Diagonal on Permutahedra (2004)

C∗ (Pn) denotes the cellular chains of Pn ∆P : C∗ (Pn) → C∗ (Pn) ⊗ C∗ (Pn) S-U agrees with A-W on P1 and P2 :

∆P () = ⊗ ∆P

  • =

⊗ + ⊗

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SLIDE 48

Left-iterated S-U Diagonal

Define ∆(0) P

:= Id and ∆(n)

P

:=

  • ∆P ⊗ Id⊗n−1

∆(n−1)

P

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SLIDE 49

Left-iterated S-U Diagonal

Define ∆(0) P

:= Id and ∆(n)

P

:=

  • ∆P ⊗ Id⊗n−1

∆(n−1)

P Denote the up-rooted n-leaf corolla by n

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SLIDE 50

Left-iterated S-U Diagonal

Define ∆(0) P

:= Id and ∆(n)

P

:=

  • ∆P ⊗ Id⊗n−1

∆(n−1)

P Denote the up-rooted n-leaf corolla by n Think of ∆(n−1) P

(m+1) as a subcomplex of (Pm)×n

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SLIDE 51

Left-iterated S-U Diagonal

Define ∆(0) P

:= Id and ∆(n)

P

:=

  • ∆P ⊗ Id⊗n−1

∆(n−1)

P Denote the up-rooted n-leaf corolla by n Think of ∆(n−1) P

(m+1) as a subcomplex of (Pm)×n

X n m =

  • vertices of ∆(n−1)

P

(m+1)

  • is a subposet of (Sm)×n
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SLIDE 52

Left-iterated S-U Diagonal

Define ∆(0) P

:= Id and ∆(n)

P

:=

  • ∆P ⊗ Id⊗n−1

∆(n−1)

P Denote the up-rooted n-leaf corolla by n Think of ∆(n−1) P

(m+1) as a subcomplex of (Pm)×n

X n m =

  • vertices of ∆(n−1)

P

(m+1)

  • is a subposet of (Sm)×n

x ∈ X n m ↔ n × 1 matrix of up-rooted trees with m + 1 leaves

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SLIDE 53

Vertices as Matrices

∆(1) P () = ⊗ implies X 2 1 =

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SLIDE 54

Vertices as Matrices

∆(1) P () = ⊗ implies X 2 1 =

  • ∆(1)

P

  • =

⊗ + ⊗ implies X 2

2 =

  • ,

,

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SLIDE 55

Vertices as Matrices

∆(1) P () = ⊗ implies X 2 1 =

  • ∆(1)

P

  • =

⊗ + ⊗ implies X 2

2 =

  • ,

,

  • Vertex of particular interest is

∈ X 4

3 ⊂ (P3)x4

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SLIDE 56

Vertices as Matrices

Y m n =

  • vertices of ∆(m−1)

P

n+1 is a subposet of (Sn)×m

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SLIDE 57

Vertices as Matrices

Y m n =

  • vertices of ∆(m−1)

P

n+1 is a subposet of (Sn)×m

y ∈Y m n ↔1 × m matrix of down-rooted trees with n + 1 leaves

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SLIDE 58

Vertices as Matrices

Y m n =

  • vertices of ∆(m−1)

P

n+1 is a subposet of (Sn)×m

y ∈Y m n ↔1 × m matrix of down-rooted trees with n + 1 leaves ∆(2) P () = ⊗ ⊗ implies Y 3 1 = {[ ]}

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SLIDE 59

Vertices as Matrices

Y m n =

  • vertices of ∆(m−1)

P

n+1 is a subposet of (Sn)×m

y ∈Y m n ↔1 × m matrix of down-rooted trees with n + 1 leaves ∆(2) P () = ⊗ ⊗ implies Y 3 1 = {[ ]} ∆(1) P

  • =

⊗ + ⊗ implies Y 2

2 =

  • ,

,

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SLIDE 60

Vertices as Matrices

Y m n =

  • vertices of ∆(m−1)

P

n+1 is a subposet of (Sn)×m

y ∈Y m n ↔1 × m matrix of down-rooted trees with n + 1 leaves ∆(2) P () = ⊗ ⊗ implies Y 3 1 = {[ ]} ∆(1) P

  • =

⊗ + ⊗ implies Y 2

2 =

  • ,

,

  • Vertex of particular interest is

∈ Y 4

3

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SLIDE 61

Vertices as Matrix Products

Trees with levels factor uniquely as matrix products of levels

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SLIDE 62

Vertices as Matrix Products

Trees with levels factor uniquely as matrix products of levels x ∈ X n m factors uniquely as a matrix product x = x1 · · · xm

∈ X 2

2

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SLIDE 63

Vertices as Matrix Products

Trees with levels factor uniquely as matrix products of levels x ∈ X n m factors uniquely as a matrix product x = x1 · · · xm

∈ X 2

2 y ∈ Y m n

factors uniquely as a matrix product y = yn · · · y1 ∈ Y 2

2

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SLIDE 64

Transverse Product

A bisequence matrix of graphs αyi xj has the form

   αy1

x1

· · · αy1

xp

. . . . . . αyq

x1

· · · αyq

xp

  

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SLIDE 65

Transverse Product

A bisequence matrix of graphs αyi xj has the form

   αy1

x1

· · · αy1

xp

. . . . . . αyq

x1

· · · αyq

xp

  

A transverse product of bisequence matrices has form

   αy1

p

. . . αyq

p

  

  • βq

x1

· · · βq

xp

  • := αy1

p · · · αyq p

βq

x1 · · · βq xp

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SLIDE 66

Block Transverse Product

A typical Block Transverse Product (BTP) has the form

α1

2

α5

2

α4

2

α3

2

α1

1

α5

1

α4

1

α3

1

β3

1

β3

2

β3

3

β1

1

β1

2

β1

3

=         α1

2

α5

2

α4

2

  β3

1

β3

2

 α1

1

α5

1

α4

1

  β3

3

  • α3

2

β1

1

β1

2

  • α3

1

β1

3

    

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SLIDE 67

Block Transverse Product

A typical Block Transverse Product (BTP) has the form

α1

2

α5

2

α4

2

α3

2

α1

1

α5

1

α4

1

α3

1

β3

1

β3

2

β3

3

β1

1

β1

2

β1

3

=         α1

2

α5

2

α4

2

  β3

1

β3

2

 α1

1

α5

1

α4

1

  β3

3

  • α3

2

β1

1

β1

2

  • α3

1

β1

3

    

The BTP acts associatively on bisequence matrices

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SLIDE 68

Vertices as BTPs

  • =
  • []
  • []
  • =
  • []
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SLIDE 69

Vertices as BTPs

  • =
  • []
  • []
  • =
  • []

Vertices of KKn,m “generated by” X n m−1 × Y m n−1 ⊂ Pm+n−2

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SLIDE 70

Vertices as BTPs

  • =
  • []
  • []
  • =
  • []

Vertices of KKn,m “generated by” X n m−1 × Y m n−1 ⊂ Pm+n−2 X 2 1 × Y 2 1 =

  • []
  • generates the vertices of KK2,2
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SLIDE 71

Vertices as BTPs

  • =
  • []
  • []
  • =
  • []

Vertices of KKn,m “generated by” X n m−1 × Y m n−1 ⊂ Pm+n−2 X 2 1 × Y 2 1 =

  • []
  • generates the vertices of KK2,2

X 2 2 × Y 3 1 =

  • [ ] ,
  • [ ] ,
  • [ ]
  • generates the vertices of KK2,3
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SLIDE 72

Matrix Transposition

A = [aij] is {, }-matrix; rows contain exactly once

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SLIDE 73

Matrix Transposition

A = [aij] is {, }-matrix; rows contain exactly once B = [bij] is {, }-matrix; columns contain exactly once

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SLIDE 74

Matrix Transposition

A = [aij] is {, }-matrix; rows contain exactly once B = [bij] is {, }-matrix; columns contain exactly once (A, B) is an (i, j)-edge pair if

aij ai+1,j bij bi,j+1 =

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SLIDE 75

Matrix Transposition

A = [aij] is {, }-matrix; rows contain exactly once B = [bij] is {, }-matrix; columns contain exactly once (A, B) is an (i, j)-edge pair if

aij ai+1,j bij bi,j+1 =

  • Typical (1, 1)-edge pair:

   

 ,

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SLIDE 76

Matrix Transposition

A = [aij] is {, }-matrix; rows contain exactly once B = [bij] is {, }-matrix; columns contain exactly once (A, B) is an (i, j)-edge pair if

aij ai+1,j bij bi,j+1 =

  • Typical (1, 1)-edge pair:

   

 ,

Not an edge pair:

   

 ,

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SLIDE 77

Matrix Transposition

If (A, B) is an (i, j)-edge pair...

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SLIDE 78

Matrix Transposition

If (A, B) is an (i, j)-edge pair... Ai∗ is the matrix obtained from A by deleting the ith row

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SLIDE 79

Matrix Transposition

If (A, B) is an (i, j)-edge pair... Ai∗ is the matrix obtained from A by deleting the ith row B∗j is the matrix obtained from B by deleting the jth column

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SLIDE 80

Matrix Transposition

If (A, B) is an (i, j)-edge pair... Ai∗ is the matrix obtained from A by deleting the ith row B∗j is the matrix obtained from B by deleting the jth column The (i, j)-transposition of AB is B∗jAi∗

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SLIDE 81

Matrix Transposition

If (A, B) is an (i, j)-edge pair... Ai∗ is the matrix obtained from A by deleting the ith row B∗j is the matrix obtained from B by deleting the jth column The (i, j)-transposition of AB is B∗jAi∗ Ex:

  • []

(1,1)-transpose

⇒ [] []

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SLIDE 82

Matrix Transposition

If (A, B) is an (i, j)-edge pair... Ai∗ is the matrix obtained from A by deleting the ith row B∗j is the matrix obtained from B by deleting the jth column The (i, j)-transposition of AB is B∗jAi∗ Ex:

  • []

(1,1)-transpose

⇒ [] []

If c = C1 · · · Cr and (Ck, Ck+1) is an (i, j)-edge pair, define

T k

ij (c) := C1 · · · C ∗j k+1C i∗ k · · · Cr

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SLIDE 83

Matrix Transposition

Iterate T on X n m−1 × Y m n−1 in all possible ways:

Zn,m =

  • T kt

itjt · · · T k1 i1j1 (u)

  • u ∈ X n

m−1 × Y m n−1

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SLIDE 84

Matrix Transposition

Iterate T on X n m−1 × Y m n−1 in all possible ways:

Zn,m =

  • T kt

itjt · · · T k1 i1j1 (u)

  • u ∈ X n

m−1 × Y m n−1

  • The vertex poset of Pn+m−2 extends to

X n

m−1 × Y m n−1 Zn,m

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SLIDE 85

Matrix Transposition

Iterate T on X n m−1 × Y m n−1 in all possible ways:

Zn,m =

  • T kt

itjt · · · T k1 i1j1 (u)

  • u ∈ X n

m−1 × Y m n−1

  • The vertex poset of Pn+m−2 extends to

X n

m−1 × Y m n−1 Zn,m Vertices of KK2,3 :

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SLIDE 86

Matrix Transposition

Iterate T on X n m−1 × Y m n−1 in all possible ways:

Zn,m =

  • T kt

itjt · · · T k1 i1j1 (u)

  • u ∈ X n

m−1 × Y m n−1

  • The vertex poset of Pn+m−2 extends to

X n

m−1 × Y m n−1 Zn,m Vertices of KK2,3 :

slide-87
SLIDE 87

Matrix Transposition

Iterate T on X n m−1 × Y m n−1 in all possible ways:

Zn,m =

  • T kt

itjt · · · T k1 i1j1 (u)

  • u ∈ X n

m−1 × Y m n−1

  • The vertex poset of Pn+m−2 extends to

X n

m−1 × Y m n−1 Zn,m Vertices of KK2,3 :

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SLIDE 88

A Vertex to be Discarded

Our 2011 construction admits all elements of Zn,m

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SLIDE 89

A Vertex to be Discarded

Our 2011 construction admits all elements of Zn,m If m + n ≥ 8, certain elements of Zn,m must be discarded

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SLIDE 90

A Vertex to be Discarded

Our 2011 construction admits all elements of Zn,m If m + n ≥ 8, certain elements of Zn,m must be discarded Consider the following vertex u ∈ X 4 3 × Y 4 3 :

   

                      

  • [ ]

=

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SLIDE 91

A Vertex to be Discarded

T 3 1,1 (u) =

   

                  

  • [ ]

=

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SLIDE 92

A Vertex to be Discarded

z = T 2 1,1T 3 1,1 (u) =

   

              

  • [ ]

= ∈ Z4,4

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SLIDE 93

A Vertex to be Discarded

z = T 2 1,1T 3 1,1 (u) =

   

              

  • [ ]

= ∈ Z4,4

The 2nd matrix above is not a bisequence matrix, however...

slide-94
SLIDE 94

A Vertex to be Discarded

∃! balanced factorization with bisequence indecomposable

factors ABC =    

   [ ]

slide-95
SLIDE 95

A Vertex to be Discarded

∃! balanced factorization with bisequence indecomposable

factors ABC =    

   [ ]

A vertex is admissible if balanced factorization is ∆P-coherent

slide-96
SLIDE 96

A Vertex to be Discarded

∃! balanced factorization with bisequence indecomposable

factors ABC =    

   [ ]

A vertex is admissible if balanced factorization is ∆P-coherent We now realize that the product AB fails to be ∆P-coherent

slide-97
SLIDE 97

A Vertex to be Discarded

Write the entries of AB in their balanced factorizations:

AB =    

   =

slide-98
SLIDE 98

A Vertex to be Discarded

Write the entries of AB in their balanced factorizations:

AB =    

   =

Up-rooted trees with same row (input) leaf sequences are

  • and
slide-99
SLIDE 99

A Vertex to be Discarded

Write the entries of AB in their balanced factorizations:

AB =    

   =

Up-rooted trees with same row (input) leaf sequences are

  • and

is not an edge of ∆P (12|3) ⊂ (P2 × P1)×2

slide-100
SLIDE 100

A Vertex to be Discarded

Write the entries of AB in their balanced factorizations:

AB =    

   =

Up-rooted trees with same row (input) leaf sequences are

  • and

is not an edge of ∆P (12|3) ⊂ (P2 × P1)×2

Since AB fails to be ∆P-coherent, vertex ABC is discarded

slide-101
SLIDE 101

The End

Happy Birthday, Don!